GREAT WALL OF CHINA History of the Great Wall of China: The Great Wall of China is the national military defense project in the cold weapon war era with the longest time and the largest amount of construction in the world. It condenses the sweat and wisdom of our ancestors and is the symbol and pride of the Chinese nation. According to historical records, since the Warring States period, more than 20 vassals and feudal dynasties have built the Great Wall. The earliest was the Chu Kingdom. To defend the nomadic or enemy countries in the north, they began to build the Great Wall. Subsequently, Qi, Yan, Wei, Zhao, Qin, and other countries also began to build their own Great Wall for the same purpose. After Qin unified the six countries, the famous emperor Qin Shihuang sent Meng Tian northward to the Xiongnu, connecting the Great Walls of various countries. From Linyao in the west to Liaodong in the east, it stretched for more than 10,...
Archimedes Greek physicist Archimedes' Biography Archimedes (287–212 BC) was a Greek physicist, mathematician, and inventor. The "Arquimedes Spiral" and the "Lever" are some of his inventions. He developed the idea of "specific gravity", called "Archimedes' Principle". Archimedes was born in the Greek colony of Siracusa, in Sicily, around 287 BC. C., Son of Phidias, a Greek astronomer, who used to gather in his home the elite of philosophers and men of science, to exchange ideas about their works. At that time, HÃeron II reigned, who was somewhat related to the family of Archimedes. Formation Archimedes studied at the School of Mathematics in Alexandria, which at the time was the intellectual center of the Greek world. He had contact with what was most advanced in the science of his time, living with great mathematicians and astronomers, including Eratosthenes of Cyrene, the mathematician who m...